Near‐Infrared‐Responsive Digital PCR‐Assisted Renal Cancer Exosomal miRNAs Insights and Regulation of Macrophage Polarization

Exosomes derived from tumors are critical agents in intercellular communication and the tumor microenvironment, offering a rich source of signatures for renal cell carcinoma (RCC) diagnosis. Conventional diagnostic techniques often suffer from limited sensitivity and can be invasive. This study presents an innovative approach using near-infrared (NIR) digital PCR (dPCR) with black phosphorus-embedded gelatin microcarriers for profiling exosomal miRNAs and modulating STAT3 signaling and macrophage polarization. Microcarriers produced via microfluidics, characterized by their phase-change and photothermal properties, are subjected to thermal cycling using a custom NIR source. The study identified a 4.2-fold increase in miR-210 levels in RCC cells (ACHN and A498) compared to normal cells (HK-2), with miR-126 and miR-30c levels decreasing by 7-9 times. Additionally, the method achieved a 20-fold enrichment of miRNA-34 in exosomes, leading to reduced STAT3 expression and decreased M2 macrophage polarization after co-incubation. This pioneering dPCR method provides a robust tool for early RCC detection through exosomal miRNA profiling and opens new avenues for therapeutic exosome engineering. The study underscores the potential of dPCR-based exosome genotyping in identifying cancer biomarkers and developing novel treatment strategies.